Much effort has been directed to integrating dental implants into surrounding bone. Ideally, a dental implant would be placed into alveolar bone, and thereafter bone would readily grow into the surface of the implant. To achieve this objective, many different surface technologies have been applied to dental implants. In some instances, the surface of the implant is roughened, grit-blasted, plasma-sprayed, or microtextured. In other instances, the surface is coated with a biological agent, such as hydroxylapatite (HA). In all of these instances, the goal is the same: Produce a surface on the dental implant into which surrounding bone will grow or bond.
Porous coatings have also been applied to surfaces of dental implants. U.S. Pat. No. 5,989,027 entitled: “Dental Implant Having Multiple Textured Surfaces” to Wagner et al. (and expressly incorporated herein by reference) teaches a dental implant having multiple textured surfaces on the same implant. One surface includes a porous coated substrate, and another surface includes a nonporous surface adapted to encourage bone growth or bonding.
Porous coatings are advantageous since bone will indeed grow into the surface of the implant. Osseointegration, to a limited extent then, has been achieved with porous coated surfaces. These surfaces though are far from ideal in terms of accepting and encouraging bone growth into the body of the implant.
Porous surfaces are often thin coatings applied to the metallic substrate of the implant. Bone surrounding the implant can only grow into the coating itself. Bone cannot grow through the coating and into the metallic substrate. The depth of bone growth into the implant is limited to the depth of the porous coating. Bone simply cannot grow completely through the implant.